Bleeding Sharpies & Shellac - Popular Woodworking Magazine

Bleeding Sharpies & Shellac

 In Shop Blog, Woodworking Blogs

I’m interrupting the garden gate series to delve into a matter that arose in the comments on a previous post, where I mentioned that I sometimes use a black Sharpie felt-tip pen to make the stripes on inlaid bees. A couple of readers responded that applying shellac on top of the marker would dissolve the ink, leading to smudges.

Having used this technique many times over the years without producing smudges, I was stumped. After reading the comments, I went to the shop and made a couple of marks on a piece of red oak scrap. (Typically I’m using white oak for the inlaid bees, but not always.) I let one dry for an hour before applying a film of Zinsser Bull’s Eye amber shellac with a foam brush (because I didn’t want to get out the shellac brush for an experiment). There was no smudge. With the other mark, I applied the shellac over the marker right away instead of giving it an hour. Still no smudge. In case the smudging was dependent on multiple brush strokes, I worked over the area a few times with the wet foam brush. Still no joy in the smudge-production department (which translates to joy for me in terms of my everyday work).

sharpie and shellac

The top mark dried for about an hour before I applied amber shellac. I coated the lower mark immediately after making it, brushing the shellac back and forth.

I know from experience with a variety of materials and techniques that results depend on variables, among them wood species, drying time, the proportion of solvent to solids in the finish, etc. So I pulled out a few scraps of different species — hard maple, mahogany, and pine — and repeated the experiment. This time I used Zinsser blond shellac, because it seems to have a higher solvent content. Here are photos of the results.

sharpie and shellac

Hard maple with blond (top) and amber (bottom). Definitely smudged.

sharpie and shellac

Mahogany with amber shellac: the ink bled into the pores as I wrote the letter with the marker. When I applied shellac, it smudged slightly.

sharpie and shellac

The original red oak sample, this time with blond shellac

I contacted the technical department at Zinsser (the brand is now owned by Rustoleum), hoping to get some informed insight into these results, but the very helpful staff person who took my call has, as of publication time, still not been able to get a response from the individual qualified to comment substantively. If I hear back, I will add the information to this post.

Bottom line: Always perform a test before applying any finish to a workpiece. And if you want to sign your work in black Sharpie, do so after applying a shellac finish.

Thanks to the readers who commented on my earlier post for providing me an opportunity to do this experiment.

Update

On applying Sharpie over shellac: I did a test last weekend and found that there was no smudging or apparent bleed-through. With any technique, always do a test that goes completely through every stage of finishing.

Sharpie on top of amber shellac

– Nancy Hiller


English Arts & Crafts Furniture
Projects & Techniques for the Modern Maker

By Nancy Hiller

English Arts & Crafts Furniture explores the Arts & Crafts movement with a unique focus on English designers. Through examination of details, techniques, and historical context, as well as projects, you’ll discover what sets these designers and their work apart from those that came before and after, as well as gain a deeper understanding of the Arts & Crafts movement and its influence.

English Arts & Crafts Furniture Projects & Techniques for the Modern Maker

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Showing 6 comments
  • keithm

    When I was first faced with removing Sharpie as a repair job, I researched and found alcohol to be the primary solvent. A cloth dampened with DNA and lightly padded over the marks took the stains right off. From their FAQ site: “The black ink in the Fine, Ultra-Fine, Twin Tip, Chisel, Retractable, Mini and Super is permanent ink. The principle solvents are alcohols, but they also contain ethylene glycol monobutyl ether. All other Sharpie ink colors are Permchrome ink. For these the principle solvents are also alcohols, but no glycol ethers are used.”

  • hickorybench

    I have a habit of decorating wood arrows with gradients of water soluble aniline dyes. The first experiment was ruined by the solvent in the finish. I next tried to apply a shellac barrier, and failed again. Then I had read that India ink is pigment and hide glue. That worked (I mixed a very thin hide glue with the dye).
    I suspect a thin hide glue barrier could be applied over the sharpie to block most finish solvents.

  • Longfatty

    Rubbermaid makes a “sharpie extreme” that might be interesting to try if you can find it. The solvents in the ink are similar but they also add some polymers that, I assume, are making the ink more durable. I think they designed it for outdoor use. It does use ethanol as a carrier solvent so I don’t think it would completely solve the problem but the ink is tougher.

    I worked in a lab for a time where we used sharpies for marking glassware. We used colors like purple and green to make it easier for the glassware technician, she could clean off the ink with just a tiny shot of alcohol or soap and water. Black held on a little longer. We used the “extreme” version when we had to cook something in a hot-water bath without washing away the labels.

    • Nancy Hiller

      That is so interesting. I often wish I had a chemist I could consult for technical matters related to woodworking. There is so much I would love to learn about the chemical dimension of my work.

  • rpattillo

    Have you tested the sharpie after shellac? Never tested it myself, but I’ve been told that Sharpies use alcohol as a solvent which then evaporates and leaves behind the black pigment/stain/whatever it is. For that reason, using a Sharpie directly on a shellac finish would re-dissolve the shellac and cause issues. Your tests above support that theory, so I’m curious why you would think Sharpie over the shellac would work. I could see it just not being an issue so long as the signature is not smudged before the alcohol from the Sharpie evaporates.

    I occasionally make growth rules as gifts for family members, and have never used shellac on them given the chance that a Sharpie might be used to mark the child’s growth. Even in that situation, it might be fine if there was another non-shellac top-coat or three.

    • Nancy Hiller

      I did a test with Sharpie on top of amber shellac. There’s an update at the end of the post.

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A great use for fast-growing oak. Rear posts for ladderback chairs, some in the bending form, others just mortised for the slats. These posts are 11⁄4" in diameter and have about 6 growth rings.